Ancient legends of Viking mariners
using mysterious sunstones to reveal the position of the sun on a cloudy
day may well be true, according to a new study.

Before
the invention of the compass, Norse adventurers travelled thousands of
kilometres across the oceans toward Greenland and most likely as far as
North America centuries ahead of Christopher Columbus.

Evidence
shows that these fearless seamen navigated by reading the position of
the sun and stars along with an intimate knowledge of landmarks,
currents and waves.